package com.ifinc.common.socket.nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;

public class NIOClient {

    /*标识数字*/
    private static int flag = 0;
    /*缓冲区大小*/
    private static int BLOCK = 4096;
    /*接受数据缓冲区*/
    private static ByteBuffer sendbuffer = ByteBuffer.allocate(BLOCK);
    /*发送数据缓冲区*/
    private static ByteBuffer receivebuffer = ByteBuffer.allocate(BLOCK);
    /*服务器端地址*/
    private final static InetSocketAddress SERVER_ADDRESS = new InetSocketAddress(
            "localhost", 8888);

    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub
        // 打开socket通道
        SocketChannel socketChannel = SocketChannel.open();
        // 设置为非阻塞方式
        socketChannel.configureBlocking(false);
        // 打开选择器
        Selector selector = Selector.open();
        // 注册连接服务端socket动作
        socketChannel.register(selector, SelectionKey.OP_CONNECT);
        // 连接
        socketChannel.connect(SERVER_ADDRESS);
        // 分配缓冲区大小内存

        Set<SelectionKey> selectionKeys;
        Iterator<SelectionKey> iterator;
        SelectionKey selectionKey;
        SocketChannel client;
        String receiveText;
        String sendText;
        int count = 0;

//        while (true) {
        //选择一组键，其相应的通道已为 I/O 操作准备就绪。
        //此方法执行处于阻塞模式的选择操作。
        selector.select();
        //返回此选择器的已选择键集。
        selectionKeys = selector.selectedKeys();
        //System.out.println(selectionKeys.size());
        iterator = selectionKeys.iterator();
        while (iterator.hasNext()) {
            selectionKey = iterator.next();
            if (selectionKey.isConnectable()) {
                System.out.println("client connect");
                client = (SocketChannel) selectionKey.channel();
                // 判断此通道上是否正在进行连接操作。
                // 完成套接字通道的连接过程。
                if (client.isConnectionPending()) {
                    client.finishConnect();
                    System.out.println("完成连接!");
                    sendbuffer.clear();
                    sendbuffer.put("Hello,Server".getBytes());
                    sendbuffer.flip();
                    client.write(sendbuffer);
                }
                client.register(selector, SelectionKey.OP_READ);
            } else if (selectionKey.isReadable()) {
                client = (SocketChannel) selectionKey.channel();
                //将缓冲区清空以备下次读取
                receivebuffer.clear();
                //读取服务器发送来的数据到缓冲区中
                count = client.read(receivebuffer);
                if (count > 0) {
                    receiveText = new String(receivebuffer.array(), 0, count);
                    System.out.println("客户端接受服务器端数据--:" + receiveText);
                    client.register(selector, SelectionKey.OP_WRITE);
                }

            } else if (selectionKey.isWritable()) {
                sendbuffer.clear();
                client = (SocketChannel) selectionKey.channel();
                sendText = "message from client--" + (flag++);
                sendbuffer.put(sendText.getBytes());
                //将缓冲区各标志复位,因为向里面put了数据标志被改变要想从中读取数据发向服务器,就要复位
                sendbuffer.flip();
                client.write(sendbuffer);
                System.out.println("客户端向服务器端发送数据--：" + sendText);
                client.register(selector, SelectionKey.OP_READ);
            }
        }
        selectionKeys.clear();
    }
//    }
}

